The joining of plastic parts to each other, either with or without reinforcing fibers in the parts, is a common and important procedure in many manufacturing processes. In general, once these bonds are formed, it is difficult to measure the bond strength non-destructively. The most common way to test the strength of a bond joint is to pull with some prescribed force on the two pieces that are bonded together to see if they come apart. In many manufactured assemblies, this is impractical, as the pieces that are bonded may be difficult to reach. Special samples can be made to test the procedure forming the bond, but such test methods do not test the actual manufactured part. The ability to determine the integrity of such bonds would have great impact in the design of machinery. For example, assurance of a robust bond between plastic parts could eliminate the need for mechanical fasteners in a number of structures.